Image-Text Ratio
Image-text ratio is the proportion of visual content to written text within an email message. Spam filters pay attention to this balance because early spammers discovered that embedding their message entirely within an image was an effective way to hide content from text-based filters.
As a result, emails composed almost entirely of images, especially a single large image with minimal or no text, are more likely to be flagged as suspicious. The ratio itself is not the only deliverability factor, but it is a consistent one.
There is no single officially correct ratio, but a widely cited guideline is a roughly 60:40 split in favour of text. The intent is not to penalise good design, but to ensure that your email’s message is readable and that you are not relying solely on images to carry all the content. An email with a beautifully designed header image, a short paragraph of text, and a text-based call to action sits well within healthy parameters.
For B2B email marketers, the practical implication is straightforward: never place critical content, your offer, your key message, or your call to action, exclusively inside an image. Write it in HTML text as well. This protects you from both spam filters and the large proportion of recipients who open emails with images turned off.
What is a good image-to-text ratio for email?
A common recommendation is that text should make up 40-60% of an email’s content. This does not mean filling emails with unnecessary words, but rather ensuring that the message, offer, and calls to action are written in HTML text and not embedded in images. The goal is a balanced, readable email that does not trigger spam filters designed to catch image-only messages.
Can a single-image email hurt my deliverability?
Yes. Emails that consist of one large image with little or no text are a classic indicator of spam in many filtering systems. If your email template uses a single hero image, add meaningful body text beneath it and ensure all important information is also present in the HTML. This protects deliverability and ensures your message lands even when images are blocked.
Does image-text ratio affect all email clients equally?
No. Different email clients and inbox providers use different filtering algorithms, and image-text ratio is just one of many signals they consider. However, because it is consistently flagged across multiple filtering systems, including those used by major corporate email servers, maintaining a healthy ratio is considered standard practice regardless of which clients your recipients use.